Hemming method and apparatus

ABSTRACT

A hemming apparatus for joining together an inside panel and an outside panel of a closure, such as a door. The apparatus includes inner and outer tools and sliding and scarfing dies supported on a frame at a bending station. The inner tool is moved into a position against an inner surface of an inside upstanding flange of the inside panel. The outer tool is pressed against an outer surface of an outside upstanding flange of the outside panel. The sliding die bends an upper portion of the outside upstanding flange over the inside upstanding flange. The scarfing die then folds the upper portion of the outside upstanding flange downward against the inside upstanding flange to complete the hem.

TECHNICAL FIELD

[0001] This invention relates generally to a hemming method and apparatus for joining together inside and outside panel portions of a closure, such as an automotive door, by hemming.

BACKGROUND OF THE INVENTION

[0002] Hemming is a well-known method for joining together inside and outside panels of a closure such as automotive door or tailgate. It is also known for inner and outer panels to be joined together by forming a hem on upstanding flanges formed along one or more edges of the panels. Forming a hem in an upstanding flange provides a panel assembly that has greater stiffness because the hem is oriented at right angles to the plane of the inside and outside panels. Also, the orientation of a hem in an upstanding flange prevents the two panels from slipping relative to one another in a direction parallel to the panels. Still further, the upstanding flange provides a surface that a seal such as a door gasket can readily be attached to.

[0003] A hemming machine configured to hem upstanding flanges generally includes an inner tool that is swung to a position against an inner surface of an inside upstanding flange of an inside panel to be joined to an outside upstanding flange in an outside panel in a subsequent hemming operation. An outer tool is pressed against an outer surface of the outside upstanding flange of the outside panel. A sliding die is then slid against an upper portion of the outside upstanding flange and bends that upper portion of the outside upstanding flange approximately 90° to a position extending over the inside upstanding flange. This pre-bent assembly is then moved to a final hemming machine where a scarfing (or wiping) die folds the upper portion of the outside upstanding flange downward against the inside upstanding flange to complete the hem.

SUMMARY OF THE INVENTION

[0004] The invention is a hemming apparatus for joining together inside and outside panels of a closure, such as an automotive door, by hemming. The apparatus includes an inner tool supported on a frame on a bending station and configured to be swung into a position against an inner surface of an inside upstanding flange of the inside panel that is to be joined to an outside upstanding flange of an outside panel in a subsequent hemming operation. The apparatus also includes an outer tool supported on the frame and configured to be pressed against an outer surface of the outside upstanding flange of the outside panel. A sliding die is also supported on the frame and is configured to bend an upper portion of the outside upstanding flange over the inside upstanding flange. A scarfing die is movably supported and configured to fold the upper portion of the outside upstanding flange downward against the inside upstanding flange to complete the hem. The scarfing die is supported at the bending station adjacent the sliding die in a position to complete the hem at the bending station so that the hem can be completed without having to move the panels to a final hemming station.

[0005] The invention also includes a method for joining together an inside panel and an outside panel of a closure, such as an automotive door, by hemming. According to this method, inside and outside panels are provided that each include an upstanding flange. The inside panel is positioned on the outside panel such that the upstanding flange of the inside panel is disposed generally parallel to an adjacent the upstanding flange of the outside panel. An upper portion of one of the two upstanding flanges is then pre-bent over the other upstanding flange at a bending station. A flange hem is then formed at the bending station by continuing to bend the upper portion of the pre-bent flange until it is generally parallel to and disposed flush against the other upstanding flange.

[0006] Objects, features and advantages of this invention include the ability to both pre-bend an upstanding flange in a panel and to form a final hem from that upstanding flange over an upstanding flange of a second panel to join the two panels at a single workstation rather than at two separate workstations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other objects, features and advantages of this invention will be apparent from the following detailed description of the preferred embodiments and the best mode, appended claims, and accompanying drawings in which:

[0008]FIG. 1 is a schematic fragmentary cross-sectional side view of inner and outer panels having respective upstanding flanges and of an inner tool, an outer tool, a sliding die and a scarfing die of a hemming apparatus constructed according to the invention, the inner and outer tools being shown in respective engaged positions and the sliding die and the scarfing die in respective retracted positions;

[0009]FIG. 2 is a schematic fragmentary cross-sectional side view of the inner and outer panels and hemming apparatus tools and dies of FIG. 1 with the inner and outer tools shown in respective engaged positions, the sliding die shown in an advanced position and the scarfing die shown in its retracted position;

[0010]FIG. 3 is a schematic fragmentary cross-sectional side view of the inner and outer panels and hemming apparatus tools and dies of FIGS. 1 and 2 with the inner and outer tools shown in respective engaged positions and the sliding and scarfing dies again shown in their respective retracted positions;

[0011]FIG. 4 is a schematic fragmentary cross-sectional side view of the inner and outer panels and hemming apparatus tools and dies of FIGS. 1 and 2 with the inner and outer tools shown in respective engaged positions, the sliding die shown in its retracted position and the scarfing die shown in its advanced position; and

[0012]FIG. 5 is a schematic front view of a structural panel bordered by the tools and dies of FIGS. 1-4 as well as three additional sets of tools and dies.

DETAILED DESCRIPTION

[0013] An apparatus 10 for joining together an inside panel 12 and an outside panel 14 of a closure 16, such as an automotive door, by hemming, is shown in the Figures. The apparatus 10 includes a first set of tools and dies 17 including an inner tool 18 movably supported on a frame (not shown) at a bending station. The inner tool 18 is supported on the frame in such a way that the inner tool 18 can be swung into a position against an inner surface 24 of an inside upstanding flange 26 of the inside panel 12. The first set of tools and dies 17 also includes an outer tool 28 that is supported on the frame in a manner allowing the outer tool 28 to be pressed against an outer surface 30 of an outside upstanding flange 32 of the outside panel 14. A sliding die 34 is also supported on the frame in a position allowing the sliding die 34 to be moved into contact with an upper portion 36 of the outside upstanding flange 32 and to bend that upper portion 36 approximately 90° over the inside upstanding flange 26.

[0014] A scarfing (or wiping) die 38 is also movably supported on the frame. The scarfing die 38 is movable diagonally downward and slightly to the left at an approximate ten degree angle (relative to vertical) against the bent upper portion 36 of the outside upstanding flange 32. The scarfing die 38 is positioned to fold the upper portion 36 downward against the inside upstanding flange 26 as the downward motion of the scarfing die 38 reaches a downward limit. The scarfing die 38 is supported at the bending station adjacent the sliding die 34 in a position to complete the hem at the bending station and without having to move the panels 12, 14 to a final hemming station.

[0015] In other embodiments, such as the one shown schematically in FIG. 5, the apparatus 10 may be adapted to service more than one flanged edge of a structural panel 16 at one time at a single bending station. According to the embodiment of FIG. 5, the apparatus 10 includes three additional sets of tools and dies 40, 42, 44 supported at the same bending station as the first set of tools and dies 17. The three additional sets of tools an dies 40, 42, 44 each have the same general configuration and operate in generally the same manner as is schematically shown in FIGS. 1-4 for the first set of tools and dies 17. The additional sets of tools and dies 40, 42, 44 are, however, shaped and positioned to engage and complement the respective contours of three additional pairs of inside and outside upstanding flanges 46, 48; 50, 52; 54, 56 disposed around a perimeter 58 of the structural panel 16.

[0016] In other embodiments, the hemming apparatus 10 may be configured to bend a plurality of upstanding flange tab pairs rather than elongated pairs of continuous upstanding flanges along each edge of a pair of panels to be joined.

[0017] In practice, inside and outside panels 12, 14 of a closure 16 can be joined along one edge by using a method that includes providing the outside panel 14 including the outside upstanding flange 32 and the inside panel 12 having the inside upstanding flange 26. The inside panel 12 is positioned on the outside panel 14 such that the upstanding flange 26 of the inside panel 12 is disposed generally parallel to adjacent upstanding flange 32 of the outside panel 14. The upper portion 36 of the outside upstanding flange 32 is then pre-bent or flanged approximately 90° degrees over the other inside upstanding flange 26 at the bending station. This is accomplished by moving the inner tool 18 into a position against the inside surface of the inside upstanding flange 26, moving an outer tool 28 into a position against the outside surface of the outside upstanding flange 32 below an upper portion 36 of the outside upstanding flange 32, and moving the sliding die 34 laterally to bend the upper portion 36 of the outer upstanding flange over the inside upstanding flange 26. The flange hem is then formed at the bending station by continuing to bend the upper portion 36 of the pre-bent outside upstanding flange 32 another 90° until it is generally parallel to and disposed flush against the inside upstanding flange 26. This is accomplished by moving the scarfing die 38 downward until it has bent the upper portion 36 of the pre-bent outside upstanding flange 32 over and against the inside upstanding flange 26. The outer tool 28 remains in place to support the inside and outside upstanding flanges 26, 32 during this final hemming operation.

[0018] This description is intended to illustrate certain embodiments of the invention rather than to limit the invention. Therefore, it uses descriptive rather than limiting words. Obviously, it's possible to modify this invention from what the description teaches. Within the scope of the claims, one may practice the invention other then described. 

What is claimed is:
 1. A hemming apparatus for joining together an inside panel and an outside panel of a closure by hemming, the apparatus comprising: an inner tool disposed at a bending station and supported and configured to move against an inner surface of an inside upstanding flange of an inside panel that is to be joined to an outside panel in a subsequent hemming operation; an outer tool disposed at the bending station adjacent the inner tool and supported and configured to move against an outer surface of an outside upstanding flange of the outside panel; a sliding die disposed at the bending station adjacent the inner and outer tools and movably supported and configured to bend an upper portion of the outside upstanding flange over the inside upstanding flange; a scarfing die movably supported and configured to fold the upper portion of the outside upstanding flange downward against the inside upstanding flange to complete the hem; and the scarfing die is supported at the bending station adjacent the sliding die in a position to complete the hem at the bending station rather than at a separate final hemming station.
 2. A hemming apparatus as defined in claim 1 in which: a second inner tool is disposed at the bending station and is movably supported and configured move against an inner surface of a second inside upstanding flange of an inside panel to be joined to an outside panel in a subsequent hemming operation; a second outer tool is disposed at the bending station and is movably supported and configured to be pressed against an outer surface of a second outside upstanding flange of the outside panel; a second sliding die is disposed at the bending station and is movably supported and configured to bend an upper portion of a second outside upstanding flange over the second inside upstanding flange; and a second scarfing die is movably supported and configured to fold the upper portion of the outside upstanding flange downward against the inside upstanding flange to complete a second hem along a second edge of the panels, the second scarfing die being disposed at the bending station adjacent the second sliding die in a position to complete the second hem at the bending station rather than at a separate final hemming station.
 3. A hemming apparatus as defined in claim 1 in which the hemming apparatus is configured to hem a plurality of upstanding flange tabs rather than a single continuous upstanding flange.
 4. A method of joining together an inside panel and an outside panel of a closure by hemming, the method including the steps of: providing an outside panel having an upstanding flange; providing an inside panel having an upstanding flange; providing the inside panel on the outside panel such that the upstanding flange of the inside panel is disposed generally parallel to and adjacent the upstanding flange of the outside panel; pre-bending an upper portion of one of the two upstanding flanges over the other upstanding flange at a bending station; and forming a flange hem at the bending station by continuing to bend the upper portion of the pre-bent flange until it is generally parallel to and disposed flush against the other upstanding flange.
 5. The method of claim 5 in which the pre-bending step includes: moving an inner tool into a position against an inside surface of the inside upstanding flange; moving an outer tool into a position against an outside surface of the outside upstanding flange below an upper portion of the outside upstanding flange; and moving a sliding die laterally to bend the upper portion of the outer upstanding flange over the inside upstanding flange.
 6. The method of claim 6 in which the pre-bending step includes causing the outer tool to remain in place to support the inside and outside upstanding flanges during a subsequent hemming operation.
 7. The method of claim 1 in which the step of forming a flange hem includes moving a scarfing die downward to fold the upper portion of the pre-bent flange over and against the other upstanding flange. 